agar

noun4

1. •
   A gelatinous substance obtained from red algae, especially Gracilaria species, used as a bacterial culture medium, in electrophoresis and as a food additive.
2. •
   A culture medium based on this material.

   • An hour before, he had been in lab, removing from the incubator his boxes of agar plates. — 2020
3. •
   agarwood
4. •
   A pattern that is periodic in both space and time covering the whole plane.